Hydraulic jack



A. ZISKA 2,231,047

HYDRAULIC JACK 3 Sheets-Sheet l INVENTOR.

0,444 Z/JV/A A ORNEY.

Feb. 11, 1941.

Filed July 14, 1959 on @w Qm an mm Feb. 11, 1941. A. ZISKA HYDRAULIC JACK Filed July 14, 19:59

3 Sheets-Sheet 2 INVENTOR. 4mm Z/J/m ATTORNEY.

m w "V w T N i-lllll Ti I A 55.25.25% I fi Feb. 11, 1941. A 2,231,047

HYDRAULIC JACK Filed July 14, 1939 3 Sheets-Sheet 5 IIIHIIIIIIII 1N VENTOR. 274x44 Patented Feb. 11, 1941 Uhliih stares HYDRAULIC JACK Adam Ziska, Wauwatosa, Wis, assignor to American Grinder 8.; Specialty Corp, Fond 'du Lac, Win, a corporation of Wisconsin 1 Application July 14, 1939, Serial No. 284,437 Z Claims. (G1. 254-42) This invention relates to a hydraulic jack. Objects of this invention are to provide a novel form of hydraulic jack which is very low and requires very little head room, which may be readily positioned beneath an automobile or other object to be lifted, and which is so made that a rocking handle is provided that controls the operation of the pump and the release of pressure from the high pressure cylinder, and which also is used in pushing, pulling or steering the chassis or body portion of the jack.

Further objects are to provide a hydraulic jack of the above character in which a handle is provided which has rotary motion for controlling the relief of pressure from the high pressure lifting cylinder, which has oscillatory motion for operating the pump, and which has sliding motion so that it may he slid forward to rigidly lock the handle to the body or chassis of the jack so that the jack and handle form one elongated rigid unit, the handle being thus temporarily locked against rocking so that the jack may be tilted up on its front wheels if so desired, as for example when it is desired to quickly pull or push the jack to a new location. When the handle is slid forwardly and locked .to the jack, the operavtor merely trundles the jack to the desired position, the handle being locked in its forward position. When the operator arrives at the new position, he unlocks the handle by a partial ro-- tary motion thereof and. thereafter slides the handle backwardly and uses the handle as a pump lever, subsequently rotating a portion of the handle to release the pressure in the lifting cylinder.

In hydraulic jacks there is ordinarily considerable wear at the point where the handle is pivoted to the chassis or body of the jack, and this wear in certain instances is enhanced because of the fact that the pressure applied to the pump is applied off center with reference to the axis of the handle.

This invention is designed to provide a hydraulic jack in which the pump is centrally located thus equalizing pressure on the yoke bearings and minimizing wear, and in which large, easily renewable yoke bearings are provided.

Further objects are to provide a novel form of hydraulic jack in which a cylindrical rack is provided axially of the pivot line of the yoke and is adapted to he slid transversely by rotation of the handle to thereby operate the relief valve, an elongated pinion being provided on the rotary portion of the handle which meshes with the cyvalves are so made that they are of very simple lindrical rack and a pinion being provided on the relief valve stem which also meshes with the rack, thereby insuring the correct pitch line relation between the two pinions and the rack, irrespective of the position of the handle. 5 In greater detail, objects of this invention are to provide a hydraulic jack in which the handle may be readily detached from the yoke without detaching the yoke from its bearings, thereby permitting a heavy, permanent pivotal connection between the yoke and the body of the jack while allowing ready detachment of the handle.

Further objects are to provide a. novel form of handle for a hydraulic jack in which the handle itself is separable into its component parts for shipping and in which it may be readily reassembled and thereafter may remain in its assembled condition though it is readily attached to and detached from the yoke of the jack when desired.

Further objects are to provide a construction in which the high pressure ports are so formed that they do not have to be plugged after drilling, thereby minimizing leaking, and in which the construction and are readily accessible.

Further objects are to provide a hydraulic jack in. which a safety valve is utilized to limit the -maximum pressure that may be produced to avoid straining of the parts, for in hydraulic in which a readily removable strainer is provided between the pump and the reservoir so that the oil or other liquid employed may be freed from any grit or sediment prior to reaching the pump,

the removability of the screen also providing for readydraining of the apparatus if it becomes necessary, and also allowing the easy inspection of the strainer.

Further objects are to provide a hydraulic jack which may be readilyand cheaply produced and which is easy to assemble.

An embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is a side elevation of the jack with parts broken away and partly in section, such section being taken on the line l--l of Figure 2.

Figure 2 is a plan view of the jack with the handle and other parts broken away.

Figure 3 is an enlarged sectional view on the line 33 of Figure 2.

Figure 4 is a sectional view, partly broken away, on the line 4-4 of Figure 3.

Figure 5 is a sectional View on the line 5--5 of Figure 4.

Figure 6 is a sectional view on the line 66 of Figure 5.

Figure '7 is a sectional detail of the portion of l the yoke which receives the handle.

Figure 8 is a sectional detail, partly broken away, of a portion of the handle.

Referring to the drawings, it will be seen that the jack comprises the body portion or chassis having the side frame bars I which are joined at their front end by a transverse axle portion 2 which projects outwardly beyond the side frame bars and carries the front wheels 3.

The side frame bars are joined adjacent their rear portion by means of the webbed casting 4 which in turn carries the ram or plunger of the jack and the pump together with the associated valves. The portion 4 of the body portion of the jack consists of an inner shell like member 5 which is internally threaded and an outer shell like member 6. The cylinder 1 is screw threaded into the shell like member 5 and projects outwardly therefrom and is spaced from the outer shell like member to provide a reservoir 8 for the oil. The front end of the cylinder 1 is threaded and receives the head 9 which is shouldered and fits into the outer end of the outer shell 6 of the reservoir. If desired, a packing gasket, not shown, may be provided between these parts.

The head 9 is provided with a packing I0 held in place by a gland H, and the piston or plunger I2 of the jack projects through the packing and gland and terminates in a cross-head l3 at its outer end. The inner end of the piston has an enlarged portion M which is provided with a leather cup l5 held in place in the usual manner, the casting or body portion 4 being recessed as indicated at I 6, to provide clearance for the end nut I! which holds the leather cup [5 in place. The cross-head is provided with a pair of upwardly projecting pins I 8 to which the retracting springs I9 are attached, the springs being symmetrically arranged as shown in Figure 2.

The lifting bell crank lever of the jack is indicated at 20 and is provided with a bifurcated front end that carries the transverse pin 2| which is pivoted to the downwardly extending lugs of the lifting head 22. The rear portion of the lever 20 is pivoted as indicated at 23 to the side frames I. The lever 20 is provided with the pivot pins 24 which are connected by means of a pair of side links 25 with the transverse pin 26 carried by the cross-head t3.

Thus it is apparent from the above description that as the piston l2 moves the cross-head to the right as viewed in Figures 1, 2 and 3, that the links 25 rock the lever 20 into an elevated position and thus raise the lifting head 22. The lifting head is maintained in a horizontal position by means of parallelogram link mechanism. This mechanism may include a pair of side links 21, see Figures 1 and 2, which are pivoted at their forward ends to downwardly extending lugs 28 formed on the head, and-at their rear ends as indicated at 29. I s

The front wheels 3 are relatively small and a pair of relatively larger rear wheels 30 are revolubly mounted adjacent the rear portion of the chassis or body of the jack.

The pump is located centrally between the side of the body portion as shown most clearly in Figure 4. Its cylinder is indicated at 3i and its plunger is indicated generally at 32.

The plunger is provided with an enlarged portion 33 and with a leather cup 34. The plunger extends through a guiding gland 35 screwed into the upper end of the cylinder.

The upper end of the plunger 32 carries a removable cup-shaped head 36 which may be locked in place by means of a split washer 3'8, such washer entering a groove portion of the plunger as shown in Figure 3. A spring '38 bears on the under side of the head 35 and raises the pump during its intake stroke. The pump plunger is stopped at the upper end of its stroke by the engagement of the enlarged portion 33 with the gland 35.

A hole 39 is drilled into the reservoir, see Figure 3, and a tubular strainer 40 is positioned Within this hole and spaced from the side walls thereof. This tubular strainer 40 is carried by a threaded plug 4;! which has a recessed or reduced portion 42 provided with apertures as shown in Figures 3 and 4. The plug is bored out so as to place the apertures in communication with the interior of the strainer. From Figure 4 it will be seen that the channel afforded by the reduced portion 42 of the plug communicates with the pump passage 43. It is to be noted that a relatively small aperture 44 extends into the pump passage 43 and at its point of junction therewith has a bevelled valve seat, the valve consisting of a steel ball 45. In View of the fact that the pump passage 43 slants downwardly as shown in Figure 4, there is no need of employing a spring to hold the ball in seated position as the ball will seat by gravity, the seating, of course, being enhanced by the oil pressure during the pressure stroke of the. plunger. The pump passage 43 communicates with the cylinder 3| of the pump by means of the small aperture 46, see Figure 4.

A relatively larger hole 41 is drilled downwardly to the pump passage 43 and a bevelled seat is formed at their point of union. A valve consisting of a steel ball 48 is provided and seats at this point. A closure plug 49 is threaded into the opening 4'! and has a reduced and recessed portion that carries a spring 50 bearing against the ball 48.

A high pressure delivery port or passage 5i leads from the opening 41 from the pump to the pressure cylinder 1, see Figures 4 and 6. This port is formed by drilling inwardly before the cylinder 1 is positioned and thus it is not necessary to plug this high pressure port 5|. A relief port 52, see Figure 5, is drilled downwardly and intersects the high pressure port 51. It is normally closed by a steel ball or relief valve 53 which cooperates with a seat as shown in Figure 5, and is controlled by a threaded relief valve stem 54 which passes through a suitable packing gland as shown in Figure 5 and terminates in a spur gear 55.

It is to be noted that the lower end of the valve stem 54 is reduced and is spaced from the enlargement 56 within which the valve or ball 53 is positioned. A discharge port 51 is provided and is drilled from the outer sideinwardly to the reservoir '8 as shown in Figure 5. The outer end of the discharge port 5'! is plugged as indicated at 58, but as this is the low pressure side of the apparatus, there is very little chance of leaking.

A safety valve port 59, see Figure 5, extends upwardly from the pump passage 43. The safety valve port 59 communicates with the discharge port 51 by means of the enlarged portion 88. 'A valve 6| in the form of a steel ball normally closes the port 59. This valve is urged downwardly by means of a plunger 82 which is urged downwardly by the spring 63. The pressure of the spring is adjusted by means of the screw plug 64 and the screw plug in turn is hidden or protected by means of the upper plug 85. Thus the maximum pressure may be determined by the adjustment of the pressure of the springs 83 in a very simple and easy manner, thus avoiding excessive or dangerous strains on the apparatus.

A yoke in the form of a hood like member 66 is provided with a transverse hub portion 61 that extends outwardly beyond the hood like portion of the yoke. This hub portion is bored out from end to end to provide an internal passage or opening 81, see Figure 4, and is mounted on relatively heavy trunnion pins 68 whose screw threaded portions 69 are threaded into the side frames i, as shown most clearly in Figure 4, such pins being preferably provided with nut heads 18. The yoke 66 continues rearwardly to provide a hollow shank 'II which removably receives the handle. This hollow shank II is provided with an internal bayonet slot I2, see Figures 3 and 7, for a purpose hereinafter to appear.

A cylindrical rack 73 is slidably mounted within the hub 61 and. meshes at all times with the spur gear 55 of the relief valve so that when the cylindrical rack 13 is slid in one direction, it opens the relief valve and when slid in the other direction, closes the relief valve, correct meshing being maintained at all times as the axial distance traveled by the threaded stem 54 of the relief valve, see Figure 5, is only a few thousandths of an inch.

The yoke 66 carries a roller M which is revoluloly mounted on a pin 15. The pin is firmly supported by a pair of lugs both of which are integral with the yoke 66. One of the lugs 16 extends laterally from the side of the yoke 65 and the other lug 11 extends downwardly from the upper wall of the yoke. Thus the roller I4 is adequately supported from the yoke. It is adapted to directly engage the pump plunger 32 and the point of engagement between the roller M and the pump plunger 32 is in the central vertical plane of the jack so that uniform bearing pressure on the trunnions 68 is obtained, thus minimizing wear.

It is preferable to provide the yoke 68 with means to limit its downward motion. This is accomplished. by providing lugs 18, see Figure 5, which abut corresponding lugs formed on the body portion 4.

The handle is shown most clearly in Figures 1, 2, 3 and 8 and comprises two tubular members '19 and 88 which may be detached during shipping but which after being received, are permanently joined by means of the screw 8I, see Figure 8. The handle is provided with a stud 82, see Figure 3, which may be inserted in the bayonet slot 12 of the shank II of the yoke portion and may be given apart turn to temporarily lock the handle in place, thereby permitting the ready attaching and detaching of the handle without disturbing the pivot bearings of the yoke structure.

The handle is provided with a control knob or control member 83 which is rigidly carried by a plunger or shank 84 which has a reduced portion 85 to thereby provide an end flange 86 and a shouldered portion 8'! between which a limiting screw 88 carried by the sleeve 88 extends, as shown in Figure 8, to thereby allow limited axial sliding motion of the knob or control member 83 of the handle. When the knob 83 is slid inwardly, a pin 89 is adapted toenter a bayonet slot 98 formed in the sleeve 88 and to lock the knob 83 in its forward position. Normally it occupies the position shown in Figure 8.

The knob 83 is connected with an elongated pinion 9I, see Figure 3, by means of an internal shaft. This internal shaft may consist of a squared section 92 which extends into the knob or control portion 83 of the handle and which is guided adjacent its end by means of a guide member 93, see Figure 8. The extreme end of the squared portion is preferably bevelled as indicated at 94 .to provide for its ready insertion within a correspondingly squared portion of a sleeve 95. The sleeve 95 has a rounded portion at its outer end which is pinned or otherwise secured to a reduced section 96 of the shaft 91.

The shaft 91 may also be provided with a guiding member 98, see Figure 8, so as to keep it centrally located so that when the handle is assembled after shipping, the squared shaft 92 will be guided into the sleeve 95.

Referring to Figure 3, it will be seen that the shaft 91 extends through a guiding disk 99 at the forward end of the sleeve I9 and is pinned to the elongated gear 9|. The outer end of the gear or pinion 9I terminates in a reduced extension I88, and when the knob 83, see Figure 8, is thrust forwardly, the extension I88 is adapted to enter an opening I8I formed in a lug I82 integral with the body portion 4, to thereby lock the handle to the body portion and allow the body portion to be tilted upwardly about its front wheels. Normally the parts occupy the position shown in Figures 3 and 8.

A spring I83 loosely surrounds the shaft 9'! and bears against the end bearing 99 at one end and against a. collar I84 pinned to the shaft 91 at its other end, thus urging the shaft 91 rearwardly.

The elongated pinion 9I meshes with the cylindrical rack 13 in all angular positions of the handle and the correct pitch line relation is maintained.

It is obvious that when the knob 83 is rotated, that the gear 9I, see Figure 3, causes the cylindrical rack 13, see Figures 3, 4 and 5, to shift laterally and to thereby rotate the gear 55 and. open or close the relief valve.

It is also clear that when the handle is slid forwardly and. the pin 89 locked in the bayonet slot 98, see Figure 8, that the projection I88, see Figure 3, enters the opening IN and locks the handle rigidly to the chassis or body portion of the jack, thus allowing the jack to be tilted up on its front wheels and transferred quickly to the desired position. Thereafter the knob 83 is unlocked and the handle is thus free to be oscillated up and down to oscillate the pump and to thus elevate the lifting head of the jack.

No excessive pressures can be produced as the safety valve will open at the desired setting and thus limit the maximum pressures that may be obtained.

Further it will be seen that by having the pump centrally located, bearing pressure on the side trunnions of the yoke portion of the handle is uniform and wear is thus reduced to a minimum. Additionally, the entire handle may be readily detached by giving the entire handle a part turn to detach the stud 82, see Figure 3, from the bayonet slot 12 in the hollow shank H of the yoke, and thus the jack body and its handle may be placed side by side and will occupy very little space.

It will be seen further that the construction is very sturdy, that it has relatively few parts, and that ample bearing areas are provided to withstand the loads imposed thereon.

Further it will be seen that complete control of the jack may be had without having the operator shift his position, as the entire control of the jack is obtained from the outer end of the handle.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A hydraulic jack comprising a body portion, a lifting head, hydraulic means for elevating said head, a pump for supplying liquid under pressure to said hydraulic means, a handle pivoted to said body portion for operating said pump, said handle having a revolubly and slidably mounted shaft, control means adjacent the outer end of said handle for revolving and sliding said shaft, a relief valve operatively connected to said shaft, whereby when said shaft is rotated, said relief valve is operated, and means provided with an aperture and carried by said body portion, said means being adapted to receive a projecting portion operatively coupled to said shaft when said shaft is slid forwardly, whereby said handle is locked to said body portion.

2. A hydraulic jack comprising a body portion, a lifting head, hydraulic means for elevating said head, a pump for supplying liquid under pressure to said hydraulic means, a relief Valve for relieving the pressure in said hydraulic means, a handle pivoted to said body portion for operating said pump, said handle having a revoluble outer end operatively connected to said relief valve for controlling said relief valve, said handle including a slidably mounted portion controlled from the outer end of said handle and said body portion having means interlocking with said slidably mounted portion when said slidably mounted portion is slid forwardly.

ADAM ZISKA. 

